Manava Dharmashastra 4.37

4.37

nekṣetodyantam ādityaṃ nāstaṃ yāntaṃ kadā cana
nopasṛṣṭaṃ na vāristhaṃ na madhyaṃ nabhaso gatam //

Let him never look at the sun, when he sets or rises, is eclipsed or reflected in water, or stands in the middle of the sky.